/* DON Memory Protocol Landing Page Styles */
/* Implements responsive design for SC-006 (320px+) */

/* ============================================
   CSS Custom Properties (Design Tokens)
   ============================================ */
:root {
    /* Colors - Professional dark tech theme */
    --color-primary: #00d4ff;
    --color-primary-dark: #00a8cc;
    --color-secondary: #7c3aed;
    --color-accent: #10b981;
    --color-background: #0a0a0f;
    --color-surface: #12121a;
    --color-surface-elevated: #1a1a24;
    --color-text: #ffffff;
    --color-text-muted: #9ca3af;
    --color-border: #2d2d3a;
    --color-error: #ef4444;
    --color-success: #10b981;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;

    /* Font sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;
    --text-6xl: 3.75rem;

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;

    /* Border radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(0, 212, 255, 0.3);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;

    /* Layout */
    --max-width: 1200px;
    --header-height: 72px;
}

/* ============================================
   CSS Reset & Base Styles
   ============================================ */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img, video {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-dark);
}

button {
    font-family: inherit;
    font-size: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

/* ============================================
   Accessibility Utilities
   ============================================ */

/**
 * Visually hidden but accessible to screen readers.
 * Use for aria-describedby hints, skip links, etc.
 */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/**
 * Skip to main content link (accessibility best practice).
 * Becomes visible on focus.
 */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-primary);
    color: var(--color-background);
    padding: var(--space-2) var(--space-4);
    z-index: 10000;
    transition: top var(--transition-fast);
}

.skip-link:focus {
    top: 0;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-text);
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-4xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }

p {
    margin-bottom: var(--space-4);
}

code {
    font-family: var(--font-mono);
    background: var(--color-surface);
    padding: var(--space-1) var(--space-2);
    border-radius: var(--radius-sm);
    font-size: 0.9em;
}

/* ============================================
   Utility Classes
   ============================================ */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.section {
    padding: var(--space-20) 0;
}

.text-center {
    text-align: center;
}

.text-muted {
    color: var(--color-text-muted);
}

.gradient-text {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ============================================
   Button Styles
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    min-height: 44px;
    min-width: 44px;
    font-weight: 600;
    font-size: var(--text-base);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: var(--color-background);
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 30px rgba(0, 212, 255, 0.5);
    color: var(--color-background);
}

.btn-secondary {
    background: var(--color-surface-elevated);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-surface);
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.btn-lg {
    padding: var(--space-4) var(--space-8);
    font-size: var(--text-lg);
}

/* ============================================
   Responsive Breakpoints
   ============================================ */

/* Mobile: 320px - 767px (base styles) */
/* Tablet: 768px - 1023px */
@media (min-width: 768px) {
    :root {
        --text-5xl: 3.5rem;
        --text-6xl: 4.5rem;
    }

    .container {
        padding: 0 var(--space-8);
    }

    .section {
        padding: var(--space-24) 0;
    }
}

/* Desktop: 1024px+ */
@media (min-width: 1024px) {
    :root {
        --text-5xl: 4rem;
        --text-6xl: 5rem;
    }

    .container {
        padding: 0 var(--space-12);
    }
}

/* ============================================
   Header Styles
   ============================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: rgba(10, 10, 15, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.logo {
    display: flex;
    flex-direction: column;
    text-decoration: none;
}

.logo-text {
    font-size: var(--text-xl);
    font-weight: 800;
    color: var(--color-text);
    letter-spacing: 0.1em;
    line-height: 1;
}

.logo-sub {
    font-size: var(--text-xs);
    font-weight: 500;
    color: var(--color-text-muted);
    letter-spacing: 0.2em;
}

.nav {
    display: none;
    align-items: center;
    gap: var(--space-8);
}

.nav-link {
    color: var(--color-text-muted);
    font-weight: 500;
    transition: color var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-text);
}

.nav-cta {
    margin-left: var(--space-4);
}

.mobile-menu-btn {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: var(--space-2);
}

.mobile-menu-btn span {
    width: 24px;
    height: 2px;
    background: var(--color-text);
    transition: all var(--transition-fast);
}

@media (min-width: 768px) {
    .nav {
        display: flex;
    }

    .mobile-menu-btn {
        display: none;
    }
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    padding-top: calc(var(--header-height) + var(--space-16));
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-title {
    font-size: var(--text-4xl);
    margin-bottom: var(--space-6);
}

.hero-subtitle {
    font-size: var(--text-lg);
    color: var(--color-text-muted);
    max-width: 600px;
    margin: 0 auto var(--space-12);
}

.metrics-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-4);
    margin-bottom: var(--space-12);
}

.metric-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    display: flex;
    flex-direction: column;
    align-items: center;
    transition: all var(--transition-normal);
}

.metric-card:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-glow);
}

.metric-value {
    font-size: var(--text-4xl);
    font-weight: 800;
    line-height: 1;
    margin-bottom: var(--space-2);
}

.metric-label {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--space-1);
}

.metric-desc {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

.hero-cta {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
    align-items: center;
}

@media (min-width: 768px) {
    .hero-title {
        font-size: var(--text-5xl);
    }

    .metrics-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .hero-cta {
        flex-direction: row;
        justify-content: center;
    }
}

/* ============================================
   Speed Race Section
   ============================================ */
.speed-race {
    background: radial-gradient(circle at top right, rgba(0, 212, 255, 0.08), transparent 50%), var(--color-background);
}

.speed-race-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-6);
    margin-top: var(--space-10);
}

.speed-panel,
.speed-sidecard {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    box-shadow: var(--shadow-md);
}

.speed-controls {
    display: inline-flex;
    padding: var(--space-1);
    border-radius: var(--radius-full);
    background: var(--color-surface-elevated);
    border: 1px solid var(--color-border);
    margin-bottom: var(--space-6);
}

.speed-mode-btn {
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-full);
    font-weight: 600;
    color: var(--color-text-muted);
    transition: all var(--transition-fast);
}

.speed-mode-btn.active {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: var(--color-background);
    box-shadow: var(--shadow-glow);
}

.speed-chart {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
    margin-bottom: var(--space-6);
}

.speed-row {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.speed-row.highlight .speed-label {
    color: var(--color-primary);
}

.speed-label {
    width: 140px;
    font-weight: 600;
}

.speed-bar {
    --bar-width: 0%;
    position: relative;
    flex: 1;
    min-height: 48px;
    border-radius: var(--radius-full);
    border: 1px solid var(--color-border);
    background: rgba(255, 255, 255, 0.05);
    overflow: hidden;
}

.speed-bar::before {
    content: '';
    position: absolute;
    inset: 0;
    width: var(--bar-width);
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
    opacity: 0.9;
}

.speed-row:not(.highlight) .speed-bar::before {
    background: linear-gradient(90deg, rgba(255, 255, 255, 0.15), rgba(255, 255, 255, 0.05));
}

.speed-row.highlight .speed-bar::before {
    opacity: 1;
}

.speed-latency {
    position: relative;
    display: inline-flex;
    align-items: center;
    height: 100%;
    padding: 0 var(--space-4);
    font-weight: 600;
    color: var(--color-background);
    mix-blend-mode: difference;
    z-index: 1;
}

.speed-summary {
    font-size: var(--text-lg);
    font-weight: 600;
}

.speed-sidecard ul {
    list-style: none;
    margin-bottom: var(--space-4);
}

.speed-sidecard li {
    margin-bottom: var(--space-3);
    color: var(--color-text-muted);
}

.speed-sidecard strong {
    color: var(--color-text);
}

@media (min-width: 1024px) {
    .speed-race-grid {
        grid-template-columns: 3fr 2fr;
    }
}

/* ============================================
   About Section
   ============================================ */
.about {
    background: var(--color-surface);
}

.section-title {
    font-size: var(--text-3xl);
    margin-bottom: var(--space-4);
}

.about-grid {
    display: grid;
    gap: var(--space-8);
    margin-top: var(--space-8);
}

.about-panel {
    background: var(--color-surface-elevated);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    box-shadow: var(--shadow-md);
}

.about-panel h3 {
    margin-top: 0;
    margin-bottom: var(--space-2);
}

.about-panel p {
    color: var(--color-text-muted);
    margin-bottom: var(--space-4);
}

.about-panel.stats {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.stat-line {
    display: flex;
    flex-direction: column;
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-lg);
    padding: var(--space-4);
}

.stat-label {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.stat-value {
    font-size: var(--text-lg);
    font-weight: 600;
}

@media (min-width: 900px) {
    .about-grid {
        grid-template-columns: 1.3fr 0.7fr;
    }
}

@media (min-width: 768px) {
    .section-title {
        font-size: var(--text-4xl);
    }
}

/* ============================================
   Demo Section
   ============================================ */
.section-subtitle {
    font-size: var(--text-lg);
    max-width: 600px;
    margin: 0 auto var(--space-12);
}

.demo-container {
    max-width: 700px;
    margin: 0 auto;
}

.demo-templates {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-3);
    margin-bottom: var(--space-6);
}

.templates-label {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

.template-btn {
    padding: var(--space-2) var(--space-4);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    color: var(--color-text);
    font-size: var(--text-sm);
    transition: all var(--transition-fast);
}

.template-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.template-btn.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: var(--color-background);
}

.demo-input-wrapper {
    margin-bottom: var(--space-4);
}

.demo-textarea {
    width: 100%;
    min-height: 200px;
    padding: var(--space-4);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    color: var(--color-text);
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    resize: vertical;
    transition: border-color var(--transition-fast);
}

.demo-textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}

.demo-textarea::placeholder {
    color: var(--color-text-muted);
}

.input-info {
    display: flex;
    justify-content: space-between;
    margin-top: var(--space-2);
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

.activate-btn {
    width: 100%;
    margin-bottom: var(--space-6);
}

.btn-icon {
    width: 20px;
    height: 20px;
}

.activate-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* Demo Results */
.demo-results {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    animation: fadeIn 0.3s ease;
}

.demo-results h3 {
    text-align: center;
    margin-bottom: var(--space-6);
}

.results-section {
    margin-bottom: var(--space-6);
}

.results-section:last-child {
    margin-bottom: 0;
}

.results-section h4 {
    font-size: var(--text-lg);
    margin-bottom: var(--space-4);
    color: var(--color-primary);
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
}

.result-item {
    text-align: center;
    padding: var(--space-4);
    background: var(--color-surface-elevated);
    border-radius: var(--radius-lg);
}

.result-label {
    display: block;
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    margin-bottom: var(--space-2);
}

.result-value {
    display: block;
    font-size: var(--text-2xl);
    font-weight: 700;
}

/* Retrieval Proof Section */
.retrieval-proof {
    background: var(--color-surface-elevated);
    border-radius: var(--radius-lg);
    padding: var(--space-4);
}

.proof-label {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    margin-bottom: var(--space-3);
}

.reconstructed-context {
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-3);
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    line-height: 1.6;
    color: var(--color-primary);
    margin-bottom: var(--space-3);
    max-height: 150px;
    overflow-y: auto;
}

.proof-note {
    font-size: var(--text-xs);
    color: var(--color-text-muted);
    margin-top: var(--space-3);
}

.proof-note code {
    background: var(--color-background);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    color: var(--color-primary);
    font-size: var(--text-xs);
}

.proof-note small {
    display: block;
    margin-top: var(--space-1);
    font-style: italic;
}

/* Demo Loading */
.demo-loading {
    text-align: center;
    padding: var(--space-8);
}

.loading-spinner {
    width: 48px;
    height: 48px;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    margin: 0 auto var(--space-4);
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Demo Limit Reached */
.demo-limit-reached {
    text-align: center;
    padding: var(--space-8);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
}

.limit-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--space-4);
}

.limit-icon svg {
    width: 100%;
    height: 100%;
    color: var(--color-text-muted);
}

.demo-limit-reached h3 {
    margin-bottom: var(--space-4);
}

.demo-limit-reached p {
    color: var(--color-text-muted);
    margin-bottom: var(--space-6);
}

/* Demo Error */
.demo-error {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid var(--color-error);
    border-radius: var(--radius-lg);
    padding: var(--space-4);
}

.error-message {
    color: var(--color-error);
    margin: 0;
    text-align: center;
}

/* ============================================
   Pricing Section
   ============================================ */
.pricing {
    background: var(--color-surface);
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--space-6);
    margin-top: var(--space-10);
}

.pricing-tier {
    background: var(--color-surface-elevated);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.tier-label {
    font-size: var(--text-sm);
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--color-primary);
}

.pricing-tier p {
    color: var(--color-text-muted);
}

.pricing-tier ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.pricing-tier li {
    padding-left: var(--space-5);
    position: relative;
    color: var(--color-text-muted);
}

.pricing-tier li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--color-secondary);
}

.pricing-cta {
    text-align: center;
    margin-top: var(--space-8);
}

.pricing-footer {
    max-width: 640px;
    margin: var(--space-8) auto 0;
}

.cta-note {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    margin-top: var(--space-3);
    margin-bottom: 0;
}

/* ============================================
   Data Center Fabric Section
   ============================================ */
.fabric {
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.05), rgba(124, 58, 237, 0.05));
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.fabric-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-8);
    align-items: stretch;
}

.fabric-panel {
    background: var(--color-surface-elevated);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    box-shadow: var(--shadow-md);
}

.fabric-panel ul {
    list-style: none;
    margin: var(--space-4) 0 var(--space-6);
}

.fabric-panel li {
    margin-bottom: var(--space-3);
    padding-left: var(--space-5);
    position: relative;
    color: var(--color-text-muted);
}

.fabric-panel li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-size: var(--text-lg);
    line-height: 1;
    top: 0.2rem;
}

.fabric .metrics-grid {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.fabric .metric-card {
    background: var(--color-surface-elevated);
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.nowrap {
    white-space: nowrap;
}

@media (max-width: 768px) {
    .fabric-panel {
        padding: var(--space-6);
    }
}

/* ============================================
   Industries Section
   ============================================ */
.industries {
    background: var(--color-background);
}

.industry-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--space-6);
}

.industry-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    box-shadow: var(--shadow-sm);
}

.industry-card h3 {
    margin: 0;
}

.industry-card p {
    color: var(--color-text-muted);
    flex: 1;
}

.industry-tag {
    align-self: flex-start;
    font-size: var(--text-xs);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
    background: rgba(0, 212, 255, 0.1);
    color: var(--color-primary);
    border: 1px solid rgba(0, 212, 255, 0.3);
}

/* ============================================
   Footer Styles
   ============================================ */
.footer {
    background: var(--color-background);
    border-top: 1px solid var(--color-border);
    padding: var(--space-16) 0 var(--space-8);
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-8);
    margin-bottom: var(--space-8);
}

.footer-tagline {
    color: var(--color-text-muted);
    font-size: var(--text-sm);
    margin-top: var(--space-2);
    margin-bottom: 0;
}

.footer-links {
    display: flex;
    gap: var(--space-12);
}

.footer-col h4 {
    font-size: var(--text-sm);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-4);
}

.footer-col a {
    display: block;
    color: var(--color-primary);
    font-size: var(--text-sm);
    padding: var(--space-1) 0;
    transition: color var(--transition-fast);
    cursor: pointer;
    text-decoration: underline;
}

.footer-col a:hover {
    color: var(--color-primary-dark);
}

.footer-bottom {
    padding-top: var(--space-8);
    border-top: 1px solid var(--color-border);
    text-align: center;
}

.footer-bottom p {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    margin: 0;
}

@media (min-width: 768px) {
    .footer-content {
        flex-direction: row;
        justify-content: space-between;
    }
}

/* ============================================
   Form Validation Error Styles
   ============================================ */

/**
 * Field error state - red border for invalid fields.
 * Applied dynamically by invitation-form.js validation.
 */
.field-error {
    border-color: var(--color-error) !important;
    box-shadow: 0 0 0 2px rgba(239, 68, 68, 0.2);
}

.field-error:focus {
    border-color: var(--color-error) !important;
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.3);
}

/**
 * Field error message - displays below invalid fields.
 * Has role="alert" for screen reader announcement.
 */
.field-error-message {
    display: none;
    color: var(--color-error);
    font-size: var(--text-sm);
    margin-top: var(--space-1);
    line-height: 1.4;
}

/* Success state for valid fields */
.field-valid {
    border-color: var(--color-success) !important;
}

/* ============================================
   Mobile Responsive (320px)
   ============================================ */
@media (max-width: 767px) {
    .hero-title {
        font-size: var(--text-3xl);
    }

    .metric-value {
        font-size: var(--text-3xl);
    }

    .results-grid {
        grid-template-columns: 1fr;
    }
}